As a biographer, Andrew Robinson has always been fascinated by "versatile people" such as Einstein, Michael Ventris (the architect who also deciphered the first European writing system) and the Indian writer Rabindranath Tagore. But Thomas Young "beats them all".

In physics, he had the temerity to contradict Newton and propose a wave theory of light. In physiology, he made significant advances in understanding the mechanisms of the eye, explaining how it focuses, defining astigmatism, and proposing the three-colour theory of how the retina detects the sensation of colour. The latter was finally confirmed in 1959 and was described by a modern scientist as "surely the most prescient work in all of psychophysics".

In the field of engineering, "Young's modulus" is a measure of elasticity that explains how different materials contract or expand. Egyptologists hail Young as one of the founders of their science. He provided key insights into deciphering the ancient Egyptian hieroglyphs on the Rosetta stone. In medicine (the one subject in which he received formal training) he also distinguished himself. In music, "Young's temperament" is a technique for tuning keyboard instruments. From languages (he coined the term Indo-European after a comparative analysis of 400 languages) to carpentry and life insurance, Young's incisive intellect has left its mark on countless disciplines.

Unfortunately, little has survived about his personal life. Many of his letters, journals and papers have disappeared. Young was born at Milverton, near Taunton, Somerset, on June 13 1773. The eldest of 10 siblings, he was sent to live with relatives soon after his birth and perhaps for this reason he does not seem to have been close to his parents. Towards the end of his life (he died just before his 56th birthday), Young wrote an autobiographical sketch. "As far as the qualities of the mind and feelings are concerned," he wrote, using the impersonal third person to describe himself, "he may be said to have been born old and to have died young." As a child he was precociously talented; by the age of 13 he had read 30 chapters of the Book of Genesis in Hebrew, a language he mastered without tuition. "Whoever would arrive at excellence must be self-taught," he once said.

A wonderful anecdote, told by Robinson, captures perfectly Young's analytical mind. While he was a student at Edinburgh University, he took up dancing. "Some fellow students came into his room soon after his first dancing lesson on the minuet and found him tracing, with ruler and compass, the various crossings of the two dancers and how he thought improvements might be introduced." Despite his achievements, Young was always a modest man. "He never laid down the law like other learned doctors," recalled one Cambridge colleague. A Quaker by upbringing, many of his contributions to knowledge were published anonymously.

In science, he was never a great experimentalist. Like Einstein, he preferred thought experiments, says Robinson. Ironically, it is for an experiment that Young is most famous today. By shining a light through two narrow slits and describing the pattern cast on a screen, Young demonstrated the interference of light. It "showed that light added to light could produce more light - or, most surprisingly, darkness". The interference pattern (aka "Young's fringes") could only be explained by an "undulatory" (or wave) theory of light. Although it took a while to catch on, by the end of the century Young's theory had supplanted Newton's "corpuscular" theory. Until, of course, Einstein upset the applecart with his 1905 paper arguing that light was a stream of particles. In fact, it turned out that light could behave either as a wave or as particles. But even in the new era of quantum physics, Young's double-slit experiment has proved an invaluable demonstration of the wave-particle duality of light.

Young memorably remarked that "scientific investigations are a sort of warfare ... against all one's contemporaries and predecessors" and he attracted more than his fair share of hostility. As well as accusations of dilettantism, he also faced criticism for his writing style, which many found wooden. It is true that Young was no master of style, which is perhaps one reason why he has never received the wider recognition he deserves.

Nevertheless, the originality of his mind cannot be denied. Young brought a formidable analytical intelligence and an uncanny ability to uncover gold nuggets of truth among disparate data. Many biographers would shy away from such a polymath. (Think of the background research.) Indeed, no one has tackled Young for 50 years. But Robinson measures up well. The Last Man Who Knew Everything is an excellent introduction to one of the most versatile minds of the 19th century.

· PD Smith is writing a cultural history of science and superweapons for Penguin